• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.175-181
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• 2003

The production of a carotenoid astaxanthin, a growth-associated principal pigment, is limited in a batch cultivation, because a high glucose concentration severely inhibits the cell growth and also influences the carotenoid production. Therefore, a fermentation strategy including effective chemicals for the high-level production of cells and astaxanthin by a mutant strain Phaffia rhodozyma AJ-6-1 was developed in a fed-batch culture. First, a production medium for maximizing the cell and astaxanthin yields was formulated and optimized. Using this optimized medium, the highest cell and astaxanthin concentrations obtained were about 38.25 g/1 and 34.77 mg/1, respectively. In addition, an attempt was made to increase the amount of astaxanthin using effective chemicals such as ethanol and acetic acid, which are known at an inducer and/or precursor of carotenoid synthesis. When either 10g/1 ethanol or 5 g/1 acetic acid was added to investigate the resulting astaxanthin content, a relatively high astaxanthin concentration or 45.62 mg/l and 43.87 mg/1, respectively, was obtained, and the cell concentrations also increased slightly under these conditions. Therefore, these results imply that a fed-batch culture of the mutant strain P. rhodozyma AJ-6-1 could be effectively employed in the commercial production of astaxanthin, although the factors affecting the productivity remain to be elucidated.

• Journal of The Korean Society of Grassland and Forage Science
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• v.33 no.4
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• pp.263-268
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• 2013

We investigated the range of linoleic acid concentrations in different forage species and harvest stages. The linoleic acid concentrations in main cultivated grasses and forage crops were analyzed at three harvesting dates in Korea. The experiment compared 19 species of main grasses and forage crops, including eight species of grasses (Perennial ryegrass, Reed canarygrass, Tall fescue, Timothy, Bromegrass, Kentucky bluegrass, Orchardgrass and Wheat grass), six legumes (White clover, Red clover, Sweet clover, Crimson clover, Alfalfa and Hairy vetch) and five forage crops (Italian ryegrass, Barley, Rye, Oat and Rape) in Korea with three cuts (8 May, 19 May and 28 May). The linoleic acid concentrations of Reed canarygrass and Timothy were the highest, and Bromegrass was the lowest among the grass species. All grass species had high concentrations of linoleic acid at the late May harvest stage but were low at the mid May harvest stage. Legumes had higher linoleic acid concentrations than those of grasses, and harvesting in mid-May resulted in the highest linoleic acid concentration. Rape had the highest linoleic acid concentration and rye showed high concentrations of linoleic acid when compared with those of forage crops. All species of grasses and forage had decreased linoleic acid concentrations by the harvest stage. We have demonstrated opportunities to change the composition of ruminant products through breeding, selection, and management of grasses for altered levels of linoleic acid as a precursor to conjugated linoleic acid.

• Transactions on Electrical and Electronic Materials
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• v.7 no.1
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• pp.26-29
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• 2006

We present the structural, magnetic, and electrical properties in the (Al,Mn)N films with various Mn concentrations grown by plasma-enhanced molecular beam epitaxy. X-ray diffraction analyses reveal that the (Al,Mn)N films have the wurtzite structure without secondary phases. All (Al,Mn)N films showed the ferromagnetic ordering. Particularly, ($Al_{1-x}Mn_{x}$)N film with x = 0.028 exhibited the highest magnetic moment per Mn atom at room temperature. Since all the films exhibit the insulating characteristics, the origin of ferromagnetism in (Al,Mn)N might be attributed to either indirect exchange interaction caused by virtual electron excitations from Mn acceptor level to the valence band within the samples or a percolation of bound magnetic polarons arisen from exchange interaction of localized carriers with magnetic impurities in a low carrier density regime.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.462-464
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• 2004

We studied the growth characteristics of carbon nanotubes which was grown from uniformly dispersed iron nanoparticles prepared from iron-acetate [Fe(II)$(CH_3COO)_2$]. The density of CNT was controlled from precursor concentrations. We also investigated the field emission properties of CNTs. We found that the optimization of CNT density is an important factor for field_emission properties.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.362-363
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• 2003

Photochemical ozone is formed from nitrogen oxides (NOx) and volatile organic compounds(VOCs) through non-linear interactions between chemical reactions and meteorology, and the relationship between precursors and photochemical ozone will be changed to match the emission distribution and meteorological fields. It is generally known that for some conditions the process of ozone formation is controlled almost entirely by NOx and is largely independent of VOC, while for other conditions ozone production increases with increasing VOC and does not increase(or sometimes even decreases) with increasing NOx (omitted)

• Biomolecules & Therapeutics
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• v.9 no.1
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• pp.20-25
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• 2001

In this study we fed control diet and tryptophan supplemented diets containing 0.35% tryptophan to ICR mice for 2 weeks. The concentrations of serotonin and 5-HIAA were changed by injection of the serotonin synthesis inhibitor, p-CPA and the serotonin precursor, serotoninP and the change of brain serotonin concentration negatively correlated with that of pain sensitivity, and p-CPA and serotoninP also changed the analgesic effect of morphine. The injection of naloxone, the opiate antagonist, resulted in an increase in the writhing frequency, but its antagonistic effect was not significant. The concentration of 5-HIAA elevated in mice brain at least 3hr after administration of morphine hydroxide indicates that the changes in brain serotonin metabolism may be associated with the acute effects of morphine analgesia. In short, these results not only suggest that tryptophan supplemented diet suppress pain sensitivity in mice, but also indicate that at least in part analgesic mechanism of serotonin may be associated with morphine analgesia.

• Textile Coloration and Finishing
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• v.8 no.2
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• pp.43-48
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• 1996

Condensation type aromatic polyimides were synthesized in DMF solvent by two step low temperature solution polymerization. By employing monomers as p-phenylene 3diamine and 3 kinds of dianhydrides such as pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride and trimellitic anhydride chloride, poly(amic acid) precursors were sythesized. These reactions were exothermic and very fast. When synthesized poly(amic acid)s were dissolved in DMF solvent and stood long time, the polymers were hydrolyzed and their degradation reactions were accelerated as the solution concentrations were dilute. Also, when water is added there-to the degradation rates were accelerated 8faster. In addition, in a very dilute solution state, the reduction viscosity is greatly increased to show properties of conventional polyelectrolytes. This also showed properties sensitive to the concentration change as carboxyl groups per unit segment are increased.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.663-663
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• 2013

We prepared Cu oxides, and Ni and Pd-TiO2@SiO2 core-shellnanostructures, and tested their CO oxidation performances by temperature-programmed mass spectrometry. We found the starting temperatures of CO oxidation are around $200^{\circ}C$ and $300^{\circ}C$ for Ni and Pd-TiO2@SiO2 nanostructures, respectively. Cu oxides are cubes with 50~200 nm with, prepared with different concentrations of NaOH and ascorbic acid. For the core-shell structures, we prepared 100 nm SiO2 spheres, first coated the surface with TiO2 precursor, and then coated with Ni and Pd. Their characteristics are further examined by scanning electron microscopy, optical microscope, FT-IR, and UV-Vis absorption spectroscopy.

• Microbiology and Biotechnology Letters
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• v.23 no.5
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• pp.556-558
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• 1995

A strain which showed cephalosporin C resistance and 7-aminocephalosporanic acid sensitivity was isolated from nature. Among the isolates, SS5 was sensitive to cephalosporin C, penicillin G, ampicillin, 7-aminocephalosporanic acid, 6-aminopenicillanic acid, and 7-aminodeacetoxy cephatosporanic acid at concentrations of 1,000 $\mu $g/ml, 2,000 $\mu $g/ml, 3,000 $\mu $g/ml, 30 $\mu $g/ml 100 $\mu $g/ml and 100 $\mu $g/ml, respectively. But SS5 was sensitive at very low concentration of chloramphenicol, kanamycin, neomycin, streptomycin and tetracycline. Since SS5 was sensitive to 7-ACA (30 $\mu $g/ml) and didn't have $\beta $-lactamase activity on the cephalosporin C, SS5 could be useful as an indicator strain for the production of 7-ACA, which is an important precursor for the synthesis of many semisynthetic cephalosporins.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.358-359
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• 2003

산업화가 급속히 진행됨에 따라 삶의 질은 향상된 반면, 대기오염으로 인한 피해는 증가하고 있다. 대기 중 존재하는 휘발성 유기화합물 (VOCs)은 인체에 독성을 가지며 암을 유발하고, 오존의 전구물질(precursor), 광화학 스모그의 원인물질, 성층권의 오존층 파괴 및 지구온난화에도 영향을 미칠 뿐 아니라 (Derwent et al., 1996) 악취를 유발하기도 한다. 악취는 황화수소(hydrogen sulfide), 메르캅탄류(mercaptans), 아민류(amines) 등 기타 자극성 있는 기체상 물질이 사람의 후각을 자극하여 불쾌감과 혐오감을 주는 냄새로 정의되며, 주로 인체의 위해성보다는 정신적ㆍ심리적인 피해를 일으키는 감각공해라고 할 수 있다 (환경부, 2002). (중략)